Protocol for Antibiotic Assays

Written by Clare Overton Lewis Created on 08 May 2014 Updated on 19 March 2018.

Samples For all antibiotic assays, 5-10mls blood into red-topped tube (no anticoagulant) DO NOT sample from the line through which the antibiotic has been given.

Antibiotic

Sampling Time

First Sample

Expected Levels

Usual interval to re-assay

VANCOMYCIN

Pre-dose only (i.e. within 15 mins before dose)

Around 2nd – 4th dose

10 – 20mg/L

3 days

GENTAMICIN / TOBRAMYCIN (b.d or t.d.s regime)

Pre-dose (within 15 mins before dose)

and

Post-dose (1hr after dose)

Around 2nd – 4th dose

Pre less than 2mg/L

Post 5 – 10 mg/L

3 days

GENTAMICIN / TOBRAMYCIN (once – daily regime)

Post-dose only taken between 6 and 14 hours after dose.

N.B. Times of dosing and sampling must be given on request form.

1st to 3rd dose

Interpretation by Microbiologist

3 days

Important Notes

After taking pre-dose levels, give the prescribed dose as normal – DO NOT wait for the results of the assay.

“Random” levels should seldom be needed and should only be taken by prior arrangement with the Duty Microbiologist.

For patients with stable renal function, whose results are within the expected range, assays do not need to be performed more than twice a week. Where renal function is unstable or poor, assays should be discussed with the Duty Microbiologist.

Protection of Personal Information – Laboratory Medicine comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database http://www.heftpathology.com/frontpage/test-database.html.Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.